We have lots of evidence that putting investments in early childhood education, even evidence from very hard-nosed economists, is one of the very best investments that the society can possibly make. And yet we still don't have public support for things like preschools.

What teenagers want most of all are social rewards, especially the respect of their peers.

Young children seem to be learning who to share this toy with and figure out how it works, while adolescents seem to be exploring some very deep and profound questions: 'How should this society work? How should relationships among people work?' The exploration is: 'Who am I, what am I doing?'

Scientists and philosophers tend to treat knowledge, imagination and love as if they were all very separate parts of human nature. But when it comes to children, all three are deeply entwined. Children learn the truth by imagining all the ways the world could be, and testing those possibilities.

Texts and e-mails travel no faster than phone calls and telegrams, and their content isn't necessarily richer or poorer.

Knowing what to expect from a teacher is a really good thing, of course: It lets you get the right answers more quickly than you would otherwise.

Adults often assume that most learning is the result of teaching and that exploratory, spontaneous learning is unusual. But actually, spontaneous learning is more fundamental.

For better or worse, we live in possible worlds as much as actual ones. We are cursed by that characteristically human guilt and regret about what might have been in the past. But that may be the cost for our ability to hope and plan for what might be in the future.

If you wanted to design a robot that could learn as well as it possibly could, you might end up with something that looked a lot like a 3-year-old.

Asking questions is what brains were born to do, at least when we were young children. For young children, quite literally, seeking explanations is as deeply rooted a drive as seeking food or water.